How elastic is Vibram rubber

Discussion in 'Gear & Footwear' started by kozz, May 1, 2013.

  1. kozz

    kozz
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    I am looking for a rubber material with good durability but a relatively low durometer. Lower than 50 but more than whatever a bicycle inner tube is. Durometer is the un-stretchiness of rubber, the higher the number, the more rigid. Most commercially available rubber is around 50 or higher.

    The purpose is to create a forefoot-protector for high-speed reps on the track. At faster speeds, the friction literally tears off chunks of skin, bringing a workout to a gory end after 1 or 2 repeats. I posted about this problem a while back.

    I solved the problem, mostly, using a loop of elastic fabric with shoe leather sewn on the outside edge of the forefoot. But it's a bit bulky and unwieldy, and leaves unprotected gaps that still get torn to bits by the friction, limiting me to about 2000 meters max of speed work on a good day. An older prototype made of bicycle tube rubber was more protective, but ripped too easily.

    Vibram rubber is, I expect, durable enough, but I don't know how stretchy it is and it's relatively expensive. Since many of you have the stuff on your minimalist shoes, maybe you can tell me. Also how thick is it? Thinner the better, as far as price.

    If I can invent a completely effective device, then I'll describe the design in another post.
     
  2. kozz

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    Bump. Does nobody really know this?

    I will rephrase the question. Vibram rubber is what percent as stretchy as a bicycle inner tube?
     
  3. randicoot

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    Well, it's not like everyone has a durometer. Vibram cherry (what was in the original Invisible shoes) is hard and not stretchy. The other Vibram rubber, which I can't think of the name right now, is softer but still doesn't stretch much.

    What about impregnating a few layers of old t-shirt with silicone sealant?
     
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  4. Barefoot Dama

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    Vibram rubber is what you need for what you're going to use it for.
    The 4mm will serve its purpose.
     
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  5. Barefoot Gentile

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    Vibram material will work for you. Vibram is the complete opposite of a inner tube.
     
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  6. BFwillie_g

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    Vibram is a gigantic company that's been making soling materials for decades. They have hundreds of formulas for God knows how many applications.

    The model 'Cherry' (which Barefoot Ted started with and Stephen at invisible shoes copied) probably is a good choice for what you need. But where to buy it? I'd start at eBay in your case.

    But what would be even better would be going to a shoe repair shop and asking to look at their sole material stock. When you find something you think'll work, ask if they'll sell you a chunk big enough for your ball protector project lol.

    There are plenty of other manufacturers. Continental, for example, who make good rubber as well. It doesn't matter whose logo is molded into the material.
     
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    Barefoot Dama and Hobbit like this.
  7. kozz

    kozz
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    No, I need something that is tougher than an inner tube, but still stretchy. I see now that Vibram is not going to work. The next prototype will be inner-tube rubber reinforced at stress points with shoe goo.
     
  8. Barefoot Gentile

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    There is always traditional racing flats.
     
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  9. Darkand

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    I've heard Vibram Super Newflex is good. It's meant to be way more flexible than than the usual Vibram rubber you see. It was mentioned to me by someone who'd made their own huaraches from it. Might be worth a look.
     
  10. Darkand

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    Oh and in the Ken Bob Saxton book he mentions how someone used PlastiDip on socks and it worked great. You can use as little or as much as you want to vary the thickness/flexibility. Just a thought.
     
  11. randicoot

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    It might just be a matter of the thickness and/or width of the rubber that accounts for the stretchiness. When I answered before I was thinking of foot sized pieces. I just went and checked some scraps and found the skinny pieces (< 1/2" wide) are quite stretchy. Are you relying on the stretchiness to hold the things to your feet? It may be a trade off--thinner is stretchier but breaks easier, thicker/wider is tougher but takes more force to stretch. I have some scraps of both the 3 mm Vibram Cherry and 6 mm Newflex I can send you if you want. I may have some larger pieces depending on how much is left over from whatever projects I have.

    I got the rubber from cobblersupplies.com but it says their site is closed for maintenance. Their phone number though is 1-440-836-3638. They had lots of different brands of soling sheets and they might be able to help you find something less expensive and stretchier over the phone.
     
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  12. kozz

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    Yes.

    The concept works, it's just a matter of finding better materials at this point. I know there must be a suitable type of rubber, but there are no wholesalers in my town.

    Rubber would be best because it sticks well to a track surface, kind of like spikes. Inner tube rubber would work if it didn't break at stress points. I tried reinforcing it with shoe goo but the stuff peels off.
     
  13. Sid

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    Did you ever figure out a solution?

    I don't know what type of track that you are running on, but it seems that modern tracks were designed specifically with shoes and spikes in mind. It may be difficult to find a barefoot/minimalist workaround.
    www.bbc.co.uk/news/science-environment-18735617
     
  14. kozz

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    Yes, I did find a solution. Unfortunately just before I did, the local track got resurfaced with knobbly-textured crap that is impossible to run fast on without shoes. I was about to test it on pavement but I got injured. And then winter came.

    If it works well maybe I will post the design, before mass-producing it and becoming a millionaire.
     
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